It really depends on what you like as you are correct. Nusa Dua is quieter and Kuta is cloer to the fun. ND is about 45vmins n cab (traffic is pretty full on around airport) from Kuta so not that far, so you can do quiet and access the fun. You probably want something with kids club and/ or a Nanny so kids have fun too. I can provide details of great Nanny in ND area if you like.
Thanks for your help. Have a great Bali holiday!